The best, fast, convenient, and easy to handle is the KD IMHO...the upper one in post #5. It is a special Ford tool, and comes marked for Model A Ford or Ford A and B, depending on when it was made. It has a simple ratchet mechanism that will hold the spring up while you fumble around. KD also made a cheaper version without the ratchet part, requiring you to hold your grip on it while getting off the keeper.
The lower tool is also a Ford special one and may be the cheaper KD...I don't remember what that one looked like.
Naturally, the good one is flea market only but is pretty common...so common that I suspect it dominated the garage market when it was an everyday item.
KD also made an excellent forged punch for the guides. And the best valve tools for flathead v8's, too!